how much timeing
Diesel Bomber
Joined: Jan 2009
Posts: 3,504
Likes: 157
From: Pylesville, Maryland
be carefull with marking the damper, remember that for every 2 turns the crank makes the pump only turns 1 time. I have timed my truck 180* off berfore and it really sucks to have to re do the process.
just make sure to doubble check your on TDC compression stroke before you time the truck and you will be fine
just make sure to doubble check your on TDC compression stroke before you time the truck and you will be fine
Diesel Enthusiast
Joined: Mar 2010
Posts: 238
Likes: 34
After buying my truck, I knew that advancing the timing was something that I wanted to do, so I set out to do a bunch of reading on the subject.
I've seen all sorts of timing advocated (as we have in this thread) and some guys are pushing the 22* or higher mark. I'm not sure that THAT much timing is really the best thing unless you are also twisting the RPM to 5000 or more.
As the RPM rises, typically, so does the need to advance the timing, as the piston is traveling fast enough that the time needed to complete the spray (which remains constant no matter the RPM) has to happen sooner in the cycle to get it done before TDC. But, if you are not cranking wild RPMs, advancing the timing too much will actually do more harm than good, as the spray will wash down the walls of the cylinder instead of hitting the bowl of the piston. (In a sense, the same thing is happening with 155* marine injectors also -- the spray pattern is wider than the piston bowl on a street 12V -- couple that with radical advanced timing and you are just running fuel down the walls of the cylinder.)
The trick is to get the timing just right (or close to that) so the cone of the spray fills the bowl of the piston as it crests the cylinder. Theoretically, that should make the most power without flooding the cylinder or diluting the oil with fuel. That "just right" mark on a street 12V seems to be right about at 16*.
I'd like to see a few dyno charts on a truck where the timing is advanced a half degree at a time to see what the curve looks like before WOT. I can see where, at WOT, the engine may make more power with an advanced timing, but only at that point. Lower in the rpm range -- where we do most of our driving -- I'd say that the power would be lower and the torque curve peakier overall.
I do know that Dodge intentionally retarded the timing on the 6BT for emmisions and longevity reasons, so bumping timing to a igher number is probably a good and healthy call for a great running engine. I know that I sure like mine now that it is at 16*. With a 3000 GSK and a #10 plate, it is downright snappy compared to before. The first day I drove my truck home (stock and sick), I could not make 50 mph going up the on-ramp to I-64 on Grinstead Drive in Louisville. Now, I can break loose the back tires and get sideways on the same ramp. Speed is not an issue... Purple haze, purple haze...
I've seen all sorts of timing advocated (as we have in this thread) and some guys are pushing the 22* or higher mark. I'm not sure that THAT much timing is really the best thing unless you are also twisting the RPM to 5000 or more.
As the RPM rises, typically, so does the need to advance the timing, as the piston is traveling fast enough that the time needed to complete the spray (which remains constant no matter the RPM) has to happen sooner in the cycle to get it done before TDC. But, if you are not cranking wild RPMs, advancing the timing too much will actually do more harm than good, as the spray will wash down the walls of the cylinder instead of hitting the bowl of the piston. (In a sense, the same thing is happening with 155* marine injectors also -- the spray pattern is wider than the piston bowl on a street 12V -- couple that with radical advanced timing and you are just running fuel down the walls of the cylinder.)
The trick is to get the timing just right (or close to that) so the cone of the spray fills the bowl of the piston as it crests the cylinder. Theoretically, that should make the most power without flooding the cylinder or diluting the oil with fuel. That "just right" mark on a street 12V seems to be right about at 16*.
I'd like to see a few dyno charts on a truck where the timing is advanced a half degree at a time to see what the curve looks like before WOT. I can see where, at WOT, the engine may make more power with an advanced timing, but only at that point. Lower in the rpm range -- where we do most of our driving -- I'd say that the power would be lower and the torque curve peakier overall.
I do know that Dodge intentionally retarded the timing on the 6BT for emmisions and longevity reasons, so bumping timing to a igher number is probably a good and healthy call for a great running engine. I know that I sure like mine now that it is at 16*. With a 3000 GSK and a #10 plate, it is downright snappy compared to before. The first day I drove my truck home (stock and sick), I could not make 50 mph going up the on-ramp to I-64 on Grinstead Drive in Louisville. Now, I can break loose the back tires and get sideways on the same ramp. Speed is not an issue... Purple haze, purple haze...
